Vegetation, in general, and forest systems, in particular, are of primordial importance in providing essential ecosystem goods and services, mitigating greenhouse gas effects, and contributing to landscape restoration. The chapters of this book underscore the importance of conducting both short- and long-term trials, as well as small and large-scale studies, to effectively monitor and assess vegetation's spatial and temporal variability and dynamics. The book highlights the convenience of proper sampling, modelling, and consideration of species traits and edaphic and climatic conditions for a comprehensive understanding of vegetation dynamics over time and across different environments. This knowledge enables the adaptation and development of management and alternative uses of the goods. Overall, understanding the ecosystems and their variability in space and time contributes to the ecosystems' sustainability, resilience and resistance to disturbances.